Side action piercing unit



United States Patent Inventor Romer H. Franzen 2714 Guillord Road, Rockford, Illinois 61 107 App]. No. 719,158

Filed April 5, 1968 Patented Nov. 24, 1970 SIDE ACTION PIERCING UNIT 7 Claims, 4 Drawing Figs.

US. Cl 83/588, 83/635 Int. Cl B26d 5/16 Field of Search 83/5 88, 590, 627, 635, 638, 581, 140,192,193

References Cited UNITED STATES PATENTS 9/1902 Low 83/627 Vance Becker Kerseg..... Granberg Killaly .4 Willis Primary Examiner-Frank T. Yost Attorney-Andrew F. Wintercorn 83/627 83/627X 83/635X 83/635X ABSTRACT: An inexpensive piercing unit is formed for operative connection to a ram of a press and is able to pierce an opening in a wall of formed parts such, for example, as cylindrically or cup-shaped workpieces by causing a piercing tool or tools to move laterally to and through an upwardly projecting wall thereof as a result of vertical movement of the press ram, this being done alone or at the same time when another tool or tools is doing vertical piercing, when necessaatemed Nov. 24,

- IIIIIIMA;

FIG .4

INVENTOR Romer H. Franzen l suns ACTION PIERCING UNIT This invention relates to a piercing unit for cutting or punching an upright wall of a formed workpiece and, more particularly, to a so-called side action piercing unit, in which a piercing tool or tools, moves laterally to pierce the sidewall, for example, of cylindrically or cup-shaped workpieces.

In many instances, generally cylindrical or cup-shaped workpieces must have their sidewalls pierced at predetermined locations, and the present piercing unit is particularly adapted for operative association with a die shoe attached to the ram of a conventional press to convert the usually vertical movement of the press ram into a lateral movement of the piercing tool or tools to pierce the sidewalls of these workpieces. Specifically, a cup-shaped workpiece is usually oriented with its sidewall to be pierced disposed generally upright, and the piercing'unit which is operable by the ram causes a tool movement which is usually substantially normal to the upright wall of the workpiece. However, direction of the tool movement maybe either substantially horizontal to pierce a substantially vertical wall -or may be inclined to the horizontal to the necessary extent to pierce an inclined wall.

In accordance with the present invention, there is provided a side action piercing unit which may be readily attached or otherwise operatively associated with a die shoe and operated by a ram of a press and is made of relatively few and heavyduty parts. Also, the piercing unit may be made inexpensively from heat-treated cold rolled steel with the exception of its operating plunger that is usually vertically disposed and is preferably made from tool steel. The preferred construction is rugged and formed of few andsimple operating elements which cooperate in a unique manner to give good accuracy and long operating life.

Accordingly, an object of the present invention is to provide an improved unit of the kind mentioned, as contrasted withthe prior art piercing units.

Other objects and advantages of the invention will become tapered key 29 engaging and sliding in a tapered keyway 31 in unit 11, the frame 13 may be made of several plates of cold rolled steel suitably fastened together, but it is preferably a one-piece,'b1ock-shaped member of heat-treated, cold-rolled steel which can be quite as easily machined to the desired form in comparison to a casting, but at substantially less overall cost. In an upper face 37 of the frame 13 is an opening or passageway which, in this instance, is, a cylindrical bore 39 which extends thefull depth of the frame from its upper face 37 to its lower face 41 that is usually bolted to a lower die shoe (not shown) supported by the bed of the press (not shown). The diameter of the bore 39 is slightly larger than the diameter of the cylindrical shank 42 on the actuator 15 and is of a size to guide the shank .and have an easy sliding fit on the latter. In other embodiments, using cast parts, which are not illustrated. the shank of the actuator was rectangular or square in cross section, and its receiving passageway in the frame 13 was of a apparent from the detailed description taken in connection 1 with the accompanying drawing, in which:

FIG. 1 is a perspective of a preferred embodiment of a piercing uniternbodyingthe invention; FIG. 2 is an enlarged sectional view taken substantially along the line 2-2 of FIG. 1;

FIG. 3 im diagrammatic view ofanother embodiment ofthe invention; and

FIG. 4 is an enlarged fragmentary view showing a tapered keyway and key.

As shown in the drawing for purposes ofillustration, the invention is embodied in a side action piercing unit 11, which, very generally, includes a supporting block or frame for attachment to a die shoe (not'shown) and an actuator or forked cam 15 which is adapted to be operatively associated with a die shoe 17 attached to a downwardly moving ram of a con-' ventional press (not shown); The actuator 15 is provided with inclined cam surfaces 19 which will slide against an inclined face or cam surface 21 (FIG. 2) on the rear end of a plunger 23 having an outer end 25 to which may be attached a piercing tool such as a punch P or cutting blade. As the ram returns upwardly, a biasing means in the form of a coiled spring 27 and return rod 28 returns the plunger 23 to the left to its retracted position.

As will be explained in greater detail, the side action piercing unit 11 of the present invention is comprised of rugged, relatively few and uncomplicated elements which are produced in a manner to provide an extremely low cost but accurate unit. Considerable reduction in cost may be realized by making the unit 11 directly from heat-treated cold rolled steel except for the plunger 23 which is preferably of oil-hardened, heat-treated tool steel. Thus, the cost of the unit may be greatly reduced in relation to the cost of using castings that still require about the same amount of machining, while still retaining good wear resistance and close accuracy of location of the pierced hole or slot. Where the piercing tool is a conventional punch which must accurately register with a die besimilar cross section. Circular cross sections are preferred for the section of bore39 and shank 42, however, as they are less costly to machine. For the purpose of receiving and guiding the plunger 23, a

plunger-receiving passageway in the form ofa cylindrical bore I 45 extends generally rearwardly from a front vertical wall43 of the frame 31. The longitudinal axis of the plunger receiving bore 45 is'generally parallel to the upper and lower faces 37 and 41 of the frame 13 and this bore intersects the actuator bore 39 at right angles. A rod guide opening 49 is also machined in the frame 13 on a line coaxially with the plungerreceiving bore 45 and extends from a rear wall 51 of the frame 13 into the actuator bore 39, whereby an inner threaded end of the return rod 28 may be inserted into the frame 13 and threadedly attached to the plunger 23.

In the embodiment of the invention illustrated in FIGS. 1 and 2, the actuator 15 includes an upper plate 53 which is generally rectangular in shape and is adapted to be attached as by suitable bolts 54 to the underside of the top die shoe 17 on the ram. Thus, the actuator 15 is attached to the top die shoe .17 and moves through a distance corresponding to the stroke of the ram. On the other hand, as will be explained in connection with FIG. 3, the actuator need not be attached to the die shoe 17 but only engaged thereby during the lower portion of the stroke of the ram.

The longitudinal axis of shank 42 of the actuator 15 is alined parallel to the vertical path of movement of the ram and is alinedto move straight downwardly in the bore 39 during the actuating stroke of the die shoe 17. On its lower end, the shank 42 is provided with a vertical bifurcating groove 57 which is sufficiently wide to provide clearance on both sides of the return rod 28 which projects through the slot 57, The slot divides the lower andforwardface of the shank 42 into a pair of spaced coplanar cam surfaces 19. The angle of these cam surfaces 19 may be varied, but here the cam surfaces are results in a maximum of Aa-inch movement of the plunger 23 v to the right.

The plunger 23 is formed from a cylindrical shaft having a front end extending outwardly of the front wall 43 of the frame 13. The front end of the plunger 23 carries a cylindrical disk 25' of nonhardened steel which can be attached after mounting of a punch P in a hole therein, not shown in FIG. 1, as of course, the location of the hole for the tool will be different for different jobs, and the screw-receiving holes made in the disk 25 and alined with holes made in the end of the plunger 23 will be made to suit the tool location. In some intion,

stances the plunger 23 may have an enlarged outer end or have a wider base plate fastened thereto, like a crosshead, as indicated in dotted lines at 23' in FIG. 2 to enable attaching a wider disk or plate 25', as shown in dotted lines in FIG. 2, whereby to enable mounting of two or more punches or blades in spaced relation on the plunger. The inner end of the plunger 23 is machined at a 60 angle to the horizontal to provide the cam face 21. To secure the return rod 28 to the plunger 23, a threaded hole 65 is provided in the inner end portion of the plunger 23 and the inner end of the return rod 28 is threaded in the hole 65. The hole 65 is coaxial with the plunger-receiving bore 45 and the opening 49 for the return rod 28,

The preferred biasing means for retracting the plunger 23 during upward movement of the ram and actuator includes the coiled spring 27 which encircles the outer end of the rod 28. Specifically, the coiled spring 27 has one end abutted against the rear wall 51 of the frame 13 and has its opposite end abutted against the inner one of a pair of jam nuts 67 threaded on the outer end of the return rod 28. When the spring 27 is unloaded and is at its freely extended length, the cam face 21 of the plunger 23 is positioned leftwardly of the position illustrated, as for example, by about seven-eighths of an inch, that being a return or retracted position for plunger 23 and the piercing tool. During rightward movement of the plunger 23 and piercing tool to the operative or piercing position illustrated, the nuts 67 compress the spring 27. After the punching operation, the actuator 15 rises and the spring 27 expands, returning the plunger 23 and piercing tool P about seven-eighths of an inch to the left.

Where the piercing tool is in. the form of a blade having a noncircular configuration, the piercing tool must be accurately alined with the receiving hole in the die (not shown) and held against turning or rotating during linear movement of the plunger 23. The plunger 23 is accordingly guided and held against turning as it slides in the bore 45 by the tapered key 29 entered in the tapered keyway 31. The keyway 31 is formed in the top of the plunger 23 and includes a pair of converging sidewalls 71 extending to a bottom, horizontally extending wall 73 (FIG. 2). The lower end of the key 31 is tapered in a complementary manner and projects into the tapered keyway 31 with its lower end 75 spaced slightly above the bottom wall 73 of the keyway. If the keyway and key begin to wear, a retaining screw '77 is threaded downwardly in a tapped hole in the block whereby its lower end forces the key 29 further downwardly into the keyway to assure sufficient contact between the key and keyway to maintain a very precise and correct alinement between the piercing tool and the receiving die.

Another embodiment of the invention is illustratedin FIG. 3, and this embodiment is particularly adapted for the piercing of the sidewalls. of cup-shaped formed members having sidewalls disposed at an incline between the vertical and horizontal. When describing this embodiment of the invenelements generally identical to those previously described are identified by the same reference numerals with the suffix a added to distinguish them from the elements of the embodiment of FIGS. land 2. g

In FIG. 3, the frame 13a is suitably supported on a block 81 shown in dotted lines and is fixed to the lower die shoe on the bed of a press with longitudinal axis of the plunger 23a and the piercing tool thereon disposed substantially normal to the wall of the workpiece (not shown). In the illustrated embodiment, the plunger 23a is disposed with its longitudinal axis at 30 to the horizontal. The rear end of the plunger 23a has a suitable cam face 21a and is biased by means of a compression spring 27a acting between the return rod 281: and a rear wall 510 of the frame 130. In this instance, the actuator 15a moves along a path which, although generally upright, is at an angle to the vertical. Specifically, the path of movement of the actuator is normal to the longitudinal axis of the plunger 23a. The lower end of the actuator 15a is formed with a cam face 19a for engaging and camming against the cam surface 21a on the plunger 23a to cause the piercing action in the manner described hereinbefore. The actuator 15a has its longitudinal axis at an acute angle to the vertical and has its upper end 83 machined or suitably ground to be horizontal and normal to the vertical. Thus, the upper end 83 of the actuator is disposed parallel to the lower face of the upper die shoe 17a to which, in this instance, is fastened a skate plate 85. It will be appreciated that as the skate plate 35 engages the upper end 83 of the actuator and forces the actuator 15a downwardly there will be a relative sliding movement between the skate plate 85 and this upper end 83 of the actuator 15a.

To assist in guiding the actuator 15a and to prevent its binding in its receiving bore 39a, the actuator 15a may be guided during its downward movement by a guide pin or set screw 87 on the frame entered in an elongated slot 89 provided in the actuator and alined parallel with the longitudinal axis of the bore 39a for the actuator. The screw 87 extends through the slot 89 and is suitably secured to the frame 130. If desired, a suitable keyway 31 and key 29 may be provided to guide alined plunger 23a during its reciprocating movement.

From the foregoing it will be seen that the side piercing unit may be formed of a relatively few and inexpensive elements which cooperate in a unique manner to punch the sidewalls of a formed workpiece. In its preferred form the side action piercing unit is quite small, but rugged, and may, for example,

have outside dimensions, exclusive of the spring, of 3- /sby 3% by 5 /2 inches with a 2-inch diameter plunger 23 or 23a and a total shut height of 4% inches,

' While a preferred embodiment has been shown and described, it will be understood that there is no intent to limit the invention by such disclosure but, rather, it is intended to cover all modifications and alternate constructions falling within the spirit andscope of the invention as defined in the appended claims. 1 1

It is believed that the foregoing description conveys a good understanding of the objects and advantages of my invention. The appended claims have been drawn to cover all legitimate modifications and adaptations I claim:

- 1. An apparatus for piercing an opening in an upwardly projecting wall of a formed metal workpiece comprising a frame having an upwardly opening passageway and having an intersecting transverse bore, a plunger reciprocable in said bore and movable laterally between a retracted position and an operative position in which a tool carried on said plunger pierces the upwardly projecting wall of the workpiece, a cam surface on the inner end of said plunger disposed at an acute angle to the path of travel for said plunger, an actuator mounted in and extending from said passageway for operative association with a ram of a press, a cam on the lower end of said actuator for engaging said cam surface on said plunger to force the latter to its operative piercing position, spring means for urging the plunger to its retracted position, and alining and guiding means on said frame for guiding said plunger to pierce the workpiece wall at an accurately located position, the matching angles of said interengaging cam and cam surface being such that the plunger and actuator are both returned to retracted position by said spring means upon return of the ram of the-press after a punching operation, the plunger being of cylindrical form and guided in a cylindrical bore in'the frame, the alining and guiding means comprising a tapered key slidable witha close working fit in a tapered keyway provided in said plunger longitudinally thereof, together with threaded means on said frame for applying endwise pressure on said key toward said keyway.

2; An apparatus for piercing an opening in an upwardly projecting wall of a formed metal workpiece comprising a frame having an upwardly opening passageway and having an intersecting transverse bore, a plunger reciprocable in said bore and movable laterally between a retracted position and an operative position in which a tool carried on said plunger pierces theupwardly projecting wall of the workpiece, a cam surface on the inner end of said plunger disposed at an acute angle to the path of travel for said plunger, an actuator mounted in and extending from said passageway for operative the horizontal, respectively, the upper end of said actuator being in a substantially horizontal plane for operative association with a vertically movable ram ofa press.

3. In combination, an apparatus as set forth in claim 2, and a generally horizontally disposed skate plate interposed between the substantially horizontal upper end of the actuator and the ram for slidable engagement on the horizontal upper reciprocation in said elongated passageway for movement between a retracted position and a piercing position in which the piercing tool pierces the workpiece wall, a cam surface on the other end of said plunger at an acute angle to its longitudina! axis, said frame having a transverse second passageway intersecting said plunger-receiving passageway, an actuator mounted in said second passageway for reciprocation along a.

path substantially normal to the path of said plunger, a cam surface on the lower end of said actuator at an acute angle to its longitudinal axis for engaging the aforesaid cam surface to move said plunger laterally to the piercing position, and spring means for returning said plunger to its retracted position, the upper end of said actuator being at an acute angle to the longitudinal axis of the actuator and disposed substantially horizontally and in the path of substantially vertical travel of the ram of a press, the matching angles of said interengaging cam surfaces being such that the plunger and actuator are both returned to retracted position by said spring means upon return of the ram of the press after a punching operation.

5. in combination, a unit as set forth in claim 4, and a generally horizontally disposed skate plate interposed between the substantially horizontal upper end of the actuator and the ram for slidable engagement on the horizontal upper end ofsaid actuator.

6. An apparatus for piercing an opening in an upwardly projecting wall of a formed metal workpiece comprising a frame having an upwardly opening passageway and having an intersecting transverse bore, a plunger reciprocable in said bore and movable laterally between a retracted position and an operative position in which a tool carried on said plunger pierces the upwardly projecting wall of the workpiece, a cam surface on the inner end of said plunger disposed at an acute angle to the path of travel. for said plunger. an actuator mounted in and extending from said passageway for operative association with a ram ofa press, the lower end portion of said actuator being forked so as to provide an opening therethrough longitudinally with respect to said plunger, the forked lower portion of said actuator having coplanar cam surfaces on one side for slidable engagement with the cam surface'on said plunger to force the latter to its operative piercing position, a rod extending from the cam surface end of said plunger through the bifurcated portion of said actuator and through a registering opening provided in said frame and projecting from the latter, and coiled compression spring means mounted on the projectingend portion of said rod and having abutment with said frame for urging the plunger to its retracted position, the matching angles of said interengaging cam surfaces on said plunger and actuator being such that the plunger and actuator are both returned to retracted position y action of said spring means upon return of the ram of the press after a piercing operation.

7. The apparatus of claim 6 in which the plunger is of cylindrical form andguided in a cylindrical bore in the frame, the apparatus including a tapered key slidable with a close working fit in a tapered keyway provided in said plunger longitudinally thereof, and means on said frame for applying endwise 

